The surface layer of an electrophotographic photosensitive member is required to have wear resistance and chemical stability because stress caused by a series of electrophotographic processes including charging, exposure, development, transfer, and cleaning is repeatedly applied to the surface layer.
A method for improving the wear resistance is, for example, a method involving incorporating a curable resin into the surface layer of the electrophotographic photosensitive member. However, when a surface layer having high wear resistance is provided, the surface layer hardly wears, and hence the surface of the surface layer is hardly refreshed and chemical deterioration is liable to accumulate on the surface. The chemical deterioration is a phenomenon in which a hole transporting substance (hole transporting compound) causes a chemical change owing to the stress caused by the series of electrophotographic processes. The chemical change of the hole transporting substance may be a cause for the occurrence of a phenomenon in which an electrophotographic image output under a high-temperature and high-humidity environment becomes blurred (hereinafter sometimes referred to as “image deletion”). Therefore, the suppression of the image deletion requires the suppression of the chemical change of the hole transporting substance.
A technology involving incorporating an additive into the surface layer together with the hole transporting substance is available as a method for improving the chemical stability of the hole transporting substance. Patent Literature 1 discloses a technology for alleviating the image deletion through the addition of a specific fluorine atom-containing monomer having a polymerizable functional group to the surface layer. Patent Literatures 2 to 4 each disclose a technology for alleviating the image deletion through the addition of a specific amine compound to the surface layer. Patent Literature 5 discloses a technology for alleviating the image deletion through the addition of a specific siloxane compound having a specific polymerizable functional group to the surface layer.